Among the studied trace elements, the first two, copper and zinc, are essential (indispensable) or real bioelements. The last four, cadmium, lead, arsenic, and mercury, are non-essential, but they are almost constantly present in body organs and tissues. In addition to the biological significance, these elements also have distinct physical features. Copper and zinc, if not introduced into the environment from copper–zinc production and use of their alloys and compounds in machinery equipment (ore mining, ore enrichment and smelting, electroplating workshops, anti-corrosion coatings, etc.) are tracers of anthropogenic impact on the environment. Lead, cadmium and mercury, topping all of the “black lists” of heavy metals due to their toxic effect on organisms in 1960–1970s, are tracers of technological environmental impact ( Khristoforova, 1989).